When you think about electronics in your Halloween or cosplay costume, you probably imagine that it does something when you do something; it’s interactive. This guide provides some tips and suggestions for adding triggers to your costumes and props. To add light to your project, check out the "Let's put LEDs in Things!" guide.
Simple momentary pushbuttons and tactile switches can be added to any part of your costume, like the trigger on your Portal gun, the back of your Star Trek communicator, or the fingers of a glove. Adafruit carries all sorts of switches in different sizes and trigger styles. Just hook one up to your Arduino or other digital I/O board and read the switch's high/low states!